The principle holding that in a warm-blooded, polytypic, wide-ranging animal species, the body size of the members of each geographic group varies with the average environmental temperature.
They are cold blooded, which means that they cannot control their own body temperature, which changes based on the temperature of the environment around them.
There are five main groups of vertebrates, the fish, the amphibians, the reptiles, the birds and the mammals. Fish, amphibians and reptiles are known as cold blooded vertebrates.
The bomb exploded in a tea shop popular with the young Iraqis in a mainly Shia district of Amil. The BBC's Haddad Salih within Baghdad said it was a particularly cold blooded attack.
The prosecutor went through the graphic, minute by minute details of the men, women and children killed and injured and what they painted as a cold blooded and premeditated attack on unarmed civilians sleeping in their homes.
" You need a woman now, " Bronn said with a glint in his black eyes. He shoved the boots into his saddlebag. " Nothing like a woman after a man's been blooded, take my word. "